Radio communication technologies have been used in various devices in recent years. Some of the devices receive radio waves by using a plurality of antenna elements (c.f. Patent Documents 1 to 3).
An actuator provided with the antenna element may execute operations corresponding to the received radio waves. Consequently, the antenna element may be suitably used in remote control of the actuator.
An antenna device, which processes signals in response to radio wave received by the antenna element and outputs control signals for controlling an operation of the actuator, is attached to or detached from the actuator if necessary. Therefore, the antenna device may be used in various technical fields.
As described above, if the antenna device is externally attached to the actuator, the antenna device may be placed in a limited place, depending on an installation position of the actuator. As the result of the placement of the antenna device in the limited place, an improvement in communication quality on the basis of diversity technologies, particularly polarization diversity, may be severely limited.
Patent Document 1: JP 2005-184713 A
Patent Document 2: JP 2007-318678 A
Patent Document 3: JP 2005-39539 A